If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

I see the contents of both the files are identical. Can anyone please explain the difference between the two. Also, if someone can precisely explain what a "listener" is used for, that would be a great help.

Hya,
The listener process is responsible to handle all connect request from client. The listener can work in 2 differen modes:
dedicated - for each connect request, the listener start a server process and hands it to the client. this server process will serve the client until it disconnects.
shared (MTS) - there are several dispathcers in the system. each dispatcher works with a server process. when a listener gets the connect request, it asks the most available dispatcher for a server process, the dispatcher is handed to the client and the client works with the dispatcher until it disconnects. In this mode, there are fewer server processes in the system.

The listener.ora file contains information about the listener, its addresss and protocol and the services it serves (the instances). The listener process uses this file for configuration.

The tnsnames.ora file is used to resolve the connect string in the connect request ("connect scott/tiger@orcl") to a database.

jmodic and pando: i did read the manuals. i am not able to decipher the conceptual difference and the use of a listener. thats why i posted. thx anyways for ur encouragement. we definitely do need some good moderators like you guys.

Originally posted by quester I see the contents of both the files are identical. Can anyone please explain the difference between the two. Also, if someone can precisely explain what a "listener" is used for, that would be a great help.

1. When the Oracle client wants to Eshtablis connection with any of the oracle servers, net8 configuration has to be done .And the details about the server will be entered in the Tnsnames File.Every time you want to connect to the server the tnsnames files will be read and the server details will be used to connect with the server.

2. The listener process will be in the Oracle Server which will be constantly listening on the port, and if any client wishes to connect to the server hands off the request to the listener and the listener takes care of the rest in authenticating and connecting.( also it will handle to request to the dispatcher in the case of Shared server mode)

Good Judgement comes from Experience.
Experience comes from Bad Judgement

the conceptual difference
The phone number you dial is the number which the other end must possess.

the use of a listener.

A telecom exchange must be ready to not only wait/standby/listen for your calls/requests but for everyone else. So after you have been connected, the exchange reliquishes the connection and waits fro others to call in...